Collins CSEC® Chemistry Workbook answers A1 States of ...

1 3 Collins CSEC Chemistry Workbook answersA1 States of matter1. a) i) Ammonium chloride (1) ii) Diffusion Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration until the particles are evenly distributed. (2) iii) The ammonia solution gave off ammonia gas and the hydrochloric acid gave off hydrogen chloride gas. The particles of the two gases diffused along the tube, collided and reacted to form ammonium chloride. (3) b) i) (1) ii) The distilled water had a higher water content than the cytoplasm inside the paw paw cells and the cell membranes were differentially permeable.

2 The water molecules were able to move through the membranes into the cells causing the cells to swell and the strips to increase in volume. (3) iii) Osmosis (1) c) Sodium chloride draws water out of the cells of the fish and any micro-organisms by osmosis. Water is, therefore, not available for chemical reactions in the cells, some of which cause decay, and micro-organisms can t grow. (2)2. a) PropertySolidLiquidGasVo l u m edefinitevariable; the volume is the same as the entire containerArrangement of particlespacked closely together, usually in a regular wayrandomly arranged with large spaces betweenEnergy of particleshave very small amounts of kinetic energyhave medium amounts of kinetic energy (6) b) i) The particles have large spaces between them, so they can be easily pushed closer together.

3 (1) ii) The particles are packed tightly together with very little empty space between. (1) iii) The particles move around rapidly and have weak forces of attraction between them, so they spread out to fill any available space in the container. (2) c) i) A: Melting B: boiling or evaporation C: Freezing D: Condensation (4) ii) Iodine or carbon dioxide or ammonium chloride or naphthalene (1) d) i) Liquid (1) ii) 56 C (1) iii) (1)A2 mixtures and separations1. a) i) Pure substanceMixtureCompositionvariablePrope rtiesfixed and constantvariable; the components retain their individual properties (3) ii) An element is a pure substance that cannot be broken down into any simpler substances by any ordinary chemical or physical means.

4 A compound is a pure substance that contains two or more different types of element that are bonded together chemically in fixed proportions and in such a way that their properties have changed. (2) b) i) The particles in a suspension are larger than those in a colloid. (1) ii) The particles in a suspension settle if left undisturbed, whereas the particles in a colloid never settle. (1) iii) Light does not pass through a suspension, whereas most colloids scatter light. (1) c) i) A solution is a homogeneous mixture consisting of two or more components, one of which is usually a liquid. (1) ii) Solubility is the mass of solute that will saturate 100 g of solvent at a given temperature.

5 (1) d) i) 17 g per 100 g water (1) ii) 45 C (1) iii) At 76 C, 54 g of Z saturate 100 g waterAt 10 C, g of Z saturate 100 g water mass of Z crystallising out of a saturated solution containing 100 g water = 54 g = g (3) iv) At 62 C, 39 g of Z saturate 100 g water at 62 C, 45 g of Z saturate 10039 45 g water = g of water (2) v) At 55 C, 33 g of Z saturate 100 g water at 55 C, 33100 350 g of Z saturate 350 g water = g of Z (2) 305/10/15 4:35 PM42. a) i) sea waterbeakersandfilter paperfilter funnel (3) ii) Simple distillation (1) iii) Leibig condenser It provides a cold surface on which the steam can condense.

6 (2) b) i) Fractional distillation (1) ii) Ethanol and water are separated based on their different boiling points . (1) c) i) A separating funnel (1) ii) They are immiscible. They have different densities. (2) d) i) Chromatography (1) ii) Sam s pen (1) iii) The solubility of the dye in the solvent used. How strongly the dye was attracted to the paper used. (2)3. a)filtrationcentrifugation (2) b) Calcium hydroxide (1) c) The cane juice is heated in a series of evaporators at successively reduced pressures and it boils at successively lower temperatures.

7 This causes the water to evaporate and the juice becomes concentrated, forming a thick syrup. (2)A3 Atomic structure1. a) i) An atom is the smallest component of an element that can exist and still have the same chemical properties as the element. (1) ii) Mass number is the total number of protons and neutrons in the nucleus of one atom of an element. (1) iii) Atomic number is the number of protons in the nucleus of one atom of an element. (1) iv) Relative atomic mass is the average mass of one atom of an element compared to one-twelfth the mass of an atom of carbon-12. (1) b) ParticleRelative massRelative chargeLocation in the atom+1in the nucleus11840spinning around the nucleusneutron1in the nucleus (7) c) A: Mass number B: Atomic number X: Atomic symbol (3) d) Nuclear notation3115P6530Zn20782Pb10847 AgName of elementphosphoruszincleadsilverNumber of protons15308247 Number of neutrons163512561 Number of electrons15308247 (4)2.

8 A) ElementPotassium Nitrogen ChlorineAtomic symbolKNClMass number1435 Atomic number19717 Number of protons197 Number of electrons717 Number of neutrons20 Electronic configuration2,8,8,12,8,7 (5) b) 4018Ar: 2,8,8 126C: 2,4 73Li: 2,1 3216S: 2,8,6 (4) c) AlOHe (3) d) 9p10n20p20n20 Cacalcium14p14n409 Ffluorine1914 Sisilicon28 (6) 405/10/15 4:35 PM53.

9 A) i) Isotopy is the occurrence of atoms of the same element which have the same number of protons and electrons but different numbers of neutrons. (1) ii) 2311Y 11 protons, 12 neutrons, 11 electrons 2511Y 11 protons, 14 neutrons, 11 electrons (2) iii) Average mass number = [85100 23] + [15100 25] = (1) iv) They both contain the same number and arrangement of electrons. (1) v) They would have slightly different masses because 2511Y has two more neutrons than 2311Y, therefore 2511Y would be slightly heavier than 2311Y. (1) b) i) An isotope with an unstable nucleus that splits spontaneously to become more stable.

10 As it splits, it ejects one or more small particles and radiation. (1) ii) A controlled beam of gamma radiation from the cobalt-60 is directed at the tumour containing the cancerous cells and it destroys the cells. (2) iii) Any three of the following: To date plant and animal remains. Isotope: carbon-14 Tracers for use in medical treatment or biological research. Suitable isotope for use in medical treatment: iodine-131. Suitable isotope for use in biological research: carbon-14 To power the batteries used in heart pacemakers. Suitable isotope: plutonium-238 To generate electricity in nuclear power stations.